In order to be able to meet the ever stricter regulations regarding the emissions, modern diesel engines comprise so-called common rail injection systems. This means a high-pressure injection system consisting of a high-pressure pump, a high-pressure store, and connecting lines, the injectors, and an electronic control unit for the control and monitoring of the injection. This is why it is usually referred to as an electronic diesel injection. The superficial benefit of the common rail injection is the reduced emission of soot. This is achieved by the finest atomization of the diesel during injection. The prerequisite for this is that both the injection pressure as well as the injection rate are constant during injection. These properties are considerably supported by a constant pressure in the store, which in turn is supported by a sufficiently large volume in the store.
For the realization of the storage function in a common rail system, there are basically two different variants known:                (1) formation of individual stores in the single injectors or in storage tanks attached to the injectors, respectively, or        (2) realisation of the store in the form of a collection line with a relatively large line diameter, from which individual supply lines each branch off to the injectors.        
The first variant has the advantage that each injector has its own store for itself, from which it is supplied, so that the individual injectors do not have much influence on each other. However, this variant has the disadvantage that it requires a relatively large amount of installation space in the region of the cylinder head and that it requires additional components and sealing points at least in the case of attached individual stores.
The second variant has the advantage that it requires relatively little installation space in the region of the cylinder head and that no additional components and sealing points are required in this region. However, it has the disadvantage that in the collection line due to the common use of it as a reservoir for the injectors pronounced pressure oscillations are present, which is disadvantageous to the injection quality and which shortens the life span of various components of the injection system.